colon polyps and cancer Flashcards

1
Q

what is a polyp?

A

growth on inner surface of colon

some undergo malignant transformation and some don’t

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2
Q

endoscopic features of colon polyps?

A

pedunculated –> attached by stem/stalk

sessile –> flat

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3
Q

what are the different types of polyps?

A
  • Hyperplastic (non-neoplastic)
  • “Pseudopolyps” (non-neoplastic) seen w/IBD
  • Adenomas (neoplastic - “pre-cancerous”)
  • Sessile serrated polyps (pre-cancerous)
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4
Q

what are the different types of adenomas (polyps)?

A

Tubular = MC
Tubulovillous
Villous

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5
Q

Adenomas are MC at what age?

A

> 50

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6
Q

why is early detection of colon polyps key?

A

70% of colorectal cancers arise from adenomas

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7
Q

characteristics of “advanced” adenomas?

A

≥ 10 mm in size
Villous component (Villous or tubulovillous)
High grade dysplasia

** Risk of CRC increases by #, size, and histology

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8
Q

what is colorectal cancer?

A

Malignant growth on the inner wall of the colon and/or rectum

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9
Q

MC site of origin of CRC?

A

LEFT side

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10
Q

Risk factors for CRC:

A

Personal or Family hx:

  • Adenomas or Colon CA
  • FAP (Familial Adenomatous Polyposis)
  • HNPCC (Hereditary nonpolyposis colon cancer)

Age >50, IBD >8-10 years, AA,

Modifiable –> smoking, excess alcohol intake, diet, T2DM, obesity

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11
Q

presentation for CRC

A

Patients are often asxs

cachectic, pallor, lymphadenopathy, abd distention, ascites, mass, oragnomegaly, DRE w/heme + stool, rectal mass

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12
Q

Red flags for CRC

A
Change in bowel habits 
Hematochezia or occult blood in stool
Iron Deficiency Anemia
Anorexia/Weight loss
Abd Pain
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13
Q

labs for CRC?

A

CBC –> Fe def anemia
LFT–> alk phos elevated w/liver mets
Carcinoembryonic –> prognostic indicator

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14
Q

diagnostic studies for CRC?

A

colonoscopy

chest/abd/pelvic CT

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15
Q

Describe the TNM system

A

Tumor – > depth of tumor invasion
Node –> regional lymph node involvement
Metastasis –> presence or absence of metastasis

Staging 0-4

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16
Q

management of CRC

A

Partial colectomy
chemotherapy (if metastasis)
radiation therapy

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17
Q

surveillance for CRC?

A

Serial CEA levels every 3-6 months for 3-5 years

CT chest/abd/pelvis annually

Colonoscopy within one year of resection (if normal repeat in 3yrs –> every 5 yrs)

18
Q

what is screening?

A

Process of detecting early-stage CRCs and precancerous lesions in asxs pts w/ no prior hx

19
Q

what is surveillance?

A

F/u testing (interval use of colonoscopy) in patients with history of polyps, CA, or IBD

20
Q

what are some preventative tests that can detect colon polyps and CRC?

A

Colonoscopy
Flex Sigmoidoscopy
CT Colonography

21
Q

what are some stool tests that can detect but don’t prevent CA?

A

gFOBT (Hemoccult SENSA)
FIT (Fecal Immunochemical Test)
FIT-DNA (Cologuard®)

22
Q

what is the gold standard for CRC screening tests?

A

colonoscpy (diagnostic AND therapeutic): ability to visualize entire colon, remove polyps, take bx’s

23
Q

describe a colonoscopy

A

Requires bowel preparation
Requires sedation/chaperone
Invasive/risk of major complications
not infallible (operator dependent & can be missed if bad prep)

24
Q

when should pt have repeat colonoscopy following a polypectomy?

A

of polyps, size, histologic features

Endoscopist provides recommendations for repeat scope

25
Q

Describe the flex sigmoidoscopy?

A

Reaches to ~ 60 cm (distal 1/3 of colon)
- can miss proximal (R-sided CA)

limited prep (enema), no sedation, lower cost, lower perf risk

26
Q

what is a CT colonography?

A

“Virtual” colonoscopy

Sensitivity of detecting polyps > 1 cm is 90%
(can miss flat or smaller polyps)

unable to remove polyps or do bx
if positive –> colonoscopy
radiation exposure

27
Q

what is the hemoccult SENSA test?

A

take-home guaiac test recommended (better sensitivity)

28
Q

what is GFOBT screening test?

A

Guaiac based test – identifies hgb by a peroxidase rxn (if + paper turns blue)

Requires two specimens on 3 consecutive stools

False + stimulates many colonoscopies

special diet recommended (red meat)

29
Q

what is the FIT screening test for CRC?

A

Noninvasive

Tests for presence of human hgb

Less false +’s than FOBT

Single specimen of spontaneously passed stool

No dietary restrictions

Preferred CRC detection test (ACG)

30
Q

what is the FIT-DNA (Cologuard) screening test?

A

Combines FIT with testing for altered DNA biomarkers in cells shed by CRC, noninvasive

requires entire BM &
> False positives than FIT

31
Q

CRC screening for average risk according to MSTF?

A

start at 50y/o unless AA than 45y/o

colonoscopy and FIT

32
Q

CRC screening for increased risk according to MSTF?

A

FHx: single 1st deg relative or advanced adenoma dx < 60 y/o OR two 1st deg relative dx any age

Single 1st degree relative w/ CRC or advanced adenoma dx ≥ 60 y/o or ≥ two 2nd degree relatives –» Begin screening at age 40 and if normal screen as average risk

33
Q

when do you discontinue CRC screening according to MSTF?

A

UTD w/screening
neg prior screen
age 75
life expectancy < 10yrs

no screening consider up to age 85y/o

34
Q

when do you discontinue CRC screening according to USPSTF?

A

Begin screening avg risk, asymptomatic adults at age 50 and continue until age 75

Decision to screen for CRC in 76-85 y/o should be individualized

35
Q

How often should prevention tests be performed?

A

colonoscopy = every 10yrs
CT colonography = every 5yrs
Flexible sigmoidoscopy = every 5-10yrs (10yrs w/annual FIT)

36
Q

how often should screening tests that detect colon cancer be performed?

A

gFOBT = annually
FIT = annually
FIT-Fecal DNA = every 1-3yrs

37
Q

what is familial adenomatous polyposis (FAP)?

A

autosomal dominant, APC gene mutation

> 100 adenomatous polyps

~ 16 y/o

will develop CRC by age 39 if untrx’d

increased risk of extracolonic malignancies

38
Q

what are extracolonic malgnancies?

A

Gastric/Duodenal/Ampullary carcinoma

Follicular/Papillary thyroid cancer

Hepatoblastoma (children)

CNS tumors

39
Q

who should receive FAP screening and what does it involve?

A

screen pts who are gene carriers or fam hx w/out genetic confirmation

Sigmoidoscopy/Colonoscopy annually starting at age 10-12 until 40 if neg

Routine EGD recommended

40
Q

what is HNPCC?

A

aka “lynch” syndrome, autosomal dominant

Increased risk for CRC (usu R-sided); aged 45-60 y/o

Multiple family members affected

Increased risk of multiple CA:
Endometrial (MC)

41
Q

Screening for HNPCC?

A

Screen w/colonoscopy every 1-2 yrs beginning at age 20-25 or 2-5 years prior to earliest age of onset of affected family member

extracolonic malignancies (pelvic exam, transvag u/s, EGD)

42
Q

what criteria is used for HNPCC diagnosis?

A

Amsterdam Criteria

“3-2-1 rule”
3 affected members, 2 generations, 1 under age 50